Teletypewriter transmitting system



Nov. 16, 1943. C WALKER I 2,334,592

TELETYPEWRITER TRANSMITTING SYSTEM Filed May 12, 1942 zz iIITH/M -E INVENTQRH (1B. [Ur/A1 ATTORNEY step-by-stepselector SLmay be, for example, of

the 204-E type well known in the art.

The step-by-step selector SL may b started in operation by a non-locking key Y. A double pole key or switch Z of the locking type is employed to connect either of the'two. tape trans-' operating winding of relay C, the armature and make contact of relay B, the upper armature and make contact of relay A and ground.

Upon the operation of relay C the upper terminals of condensers K1 and K2 will again be grounded, the grounding circuit including the second upper blade of relay C and its make contact. Thecondensers K1 and K2 will, therefore, discharge so as to prepare these condensers for a subsequent surge of current. As the voltage across condensers K1 and K2 drops below its former mitters TXD]. or TXDz to the timing circuit, to

be more fully described hereinafter. It will be understood, of course, that a multi-pole key, such.

as Z, having additional blades may be employed g to control the transmission from any number of tape transmitters.

the selector equipment energized after its energization is started in order to fully return the selector arm S to its original or starting position.

A relay D is also connected to the circuit to maintain the'release magnet RL of "Assume that properly prepared tape T has been inserted into the transmitter-distributor TXD1, and e that this transmitter-distributor has been connected to the circuit arrangement of this invention by moving the lever of the key Z to the top position. The mechanism may then be started by operating'the key Y, thekey Y releasing shortly after it is operated. Upon the'operation of key Y the stepping magnet OP of the selector will be energized by the flow of current through its winding over a circuit which includes battery E0, themagn'et OP; the key K and ground. The energization of -the stepping magnet OP will attract the stepping pawl SP until it engages the teeth of the ratchet wheel WH and advances the stepping arm S one step to contact #1.

The movement of selector arm S from contact,

#0 to contact #1 releases switch OF so that switch OF may reach its operated position. ;Upon the operation of the switch OF the relay A will become operated over a circuit which includes the battery E1 which is'connected to the lower terminal of the relay A, thewinding'of relay A, the make-before-break 1 contact associated with the upper innerblade of relayC, the lower contact of switch OE and ground. The-operation of relay A will complete a circuit for the filament of the tube VT, the completed circuit including the battery E2, resistor R3, the filament of tube VT, the lower armature and make contact of relay A, the resistor R4 and ground.

It will be observed that the condensers K1 and Kzwhich are in parallel relationshipwith each otherare grounded at their upper terminal when the relay'A is released, the grounding circuit including the make-before-bre'ak contact associated with the upper armature of relay A. Upon the operation of relay A, however, the grounding circuit for condensers K1 and K2 is removed, and the condensers are then charged by current which flows to the condensers over a circuit which ineludes battery E2, resistor R5, condensers K1'and value, the potential on the grid of the tube VT will be such as to reduce the flow of current through the plate circuit of tube VT previously described, and, therefore relay B will become releasedl Altlfiough relay B controls the start of the operation of relay C, relay C, however, will remainoperated after relay B releases due to the completion of a locking circuit for relay C, the locking circuit including battery E5, resistor R7, the upper or lockingwinding of relay C, the upper outer armature and make contact of relay C, the upper left swingerof key Z, the bounce contact W of the transmitter-distributor TXD1 and ground. *The bounce contact W is an element of the transmitter-distributor which, as is well known, is in its-closed position when the commutator brush BR of the transmitter-distributor TXD1 is on its so-called stop segment. Soon after the commutator brush BR starts rotating, however,this-bounce contact is opened and remains open until the brush BR returns to its stop or rest position.

The operation of the relay C also causes the magnet MG of the transmitter-distributor to be energized, the energizing circuit for the magnet MG including the battery E6, the resistor R8, the magnet MG of the transmitter-distributor TXD1, the upper right swinger of key Z, the lower inner blade andmake contact of relay C, the upper armature and outermost make contact of relay C, the upper left swinger of .key Z, the bounce contact W of thetransmitter-distributor TXD1 and ground. The energization of the magnet MG causes the commutator brush BR to be released by its armature, enabling it to rotate in the usual manner for the. purpose of transmitting one of the teletypewriter characters punched in the tape over the line 11130 a distant point. The relay C is locked in its operated position through the bounce contact W of the transmitter-distributor TXDi so as to .maintain'relay C-operated unt l the brush armBR starts to rotate. This permits the magnet MG to become energized long enough to fully release its associated brush BR. This is an important feature of this circuit. Without this added feature it would be possible for the magnet MG to become released before the commutator brush BR was started in rotation in the usual way for transmitting a teletypewriter character. Thus it will be observed that the relay C operates and is maintained in an operated condition to energize the magnet MG for a suflicient length of time, thereby properly actuating the brush mechanism ofthe transmitter-distributor.

The operation of the relay C also causes the stepping magnet OP of the selector SL to be again energized for stepping the selector arm S from its contact #1 to its next contact #2. The circuit for energizing the stepping magnet OP includes battery as, the operating winding OP, the upper contacts of the off-normal switch OF, the lower armature of relay C and its make contact and ground. 'Thus it will be observed that relay C when operated causes the selector arm S to step to its next contact line at themameitlme :net to 'tz 'ansmit a group of pansesoocms onmngzto a teiety'pewfiter diameter. 7 I i 1 Elhe GPEnItiDn- QIJ reIay' C also opens the' op'erating cireuit I01 riay A at the mbike be fdrebreak eunuch :as'sbciaited fiche upper inner made of reiaiy mpthemty' ailcwmg remy :A towemome released. The operation o'f 'reiwy C will ,i munu upper temnnalfif eonuensers K1 can an "mango the seam diflper iblafle er '0, thereby discharging We a g Freleasenf rr'elay a inlmnt df tube be s ew: at 71319 make contact Zi'f'fl'fe lower armature whens/m, .rereaseoi relay Anal! apply an afiaitionfiigmunu to "the opper e! the oon dezrseiski-anuk me'over mie operauon or I eTay 'C the releese oi-nefiy LA rzesult in the of th'e grid of tube vzr to ename, thereb redncnrg the plate current substantiaiiy' mo zero. relay 13 Wm become Morebverj aftr of the trazrsmitter nistnbutor TXD1 has started in 'mtafibn, its pounce wean be opened, thereby opening the docking circuit ior 0. Relay 3 win then also releis'e. 7

After relay heoome released, the relay n will become ireoperateti the operating eircuit of relay n -being Sme' is iprevi'ouslydescnbsd. The lower make contact bfrelay A will, therefore, complete the filament circuit for tube With relay reoriented and reiayC released, ground :is'agam removed from the upper-terminals of mnnmsers-xi :and and thesecom densers Pare recharged ras heretofore. nfte'rth'e voltage owthe conuensers m and K2 reaches the predetermined voltage previousiy noted, in the plate circuit of tube W' will Kgahiliowdn substantieimagnitude, thereby rebperatini relay 13. Upon the reopemtion of relayB, "thfe reiazy'c e become :reoperated; ies-already explained.

The reopemtion of reiay c will cause tiiestep- "ping magnet 0? 'of the *sel'ector sh to 'be r'eh energized; the 'reemergizing 2 circuit being 5mm pleted through the upper contact of theswitch OF and the lower armatilre and make contact of relay C. When the stepping magnet OP be comes reenergized, it will cause the selector arm S to bemoved to its next "contact #3. The ma net MG of the transmitter-distributor TXDi will also'be reenergized due totheoperation of relay C, the circuit for the magnet MG beingthe same as already described "hereina bove. Themag net MG will then again release the brushaarm BR of the transmitter-distributorwTXDi 1again allowing the brush medianis'm to transmit a series of pulses over line L corresponding to the second character punched in thetape'lfiy 1 Itwill'be observed tha't e interval. of time between the beginning of the first series of the pulses corresponding v.tothe first character transmitted. over line L pursuant to the closure of the contact #2 of the selector'arm S and the beginning of the second series of pulses corresponding to the next character 'tra' r ismitten-l when the selector arm 5 closed its next contact itfi is determined by the timing circuit which includes, among other things, the condensersfKl nd K2. The time interval between the'be'glnhifn 's jo'f the two pulses is independent of the spacing between the two charactersas punched in the tape T inserted in transmitter-'clist'ributor' 'IXDi. The

time interval is also independent or tne speed or machine TXDi. Thus the interval oitiin'e be- Upnthe subsequent iiilening or the temiee sonnet- W, the eisty-c win seam be-reieesea to reope" meme relay a. 'rebm'rauea ef'me relay swarm-en anew the eenoensers K1 and K2 I to become rechargefl;-thejrelay E to beeemegreg and "the relay C' 'nierearter erated so as "t fallbw the' steppihg magnet on e: the

seiec mrsil tobecoine'renergizeo, wheieupdn the arm-tithe esteem mechanism s winbe-movea was next "reef magnet me win also beomemenergie'eoto transmit a-thirfi char:-

acte'rj c'vei the line in. V It win beebser ve, therefore, that one charoctet-is transirutted wnen the mm "s or these meter mechanism SL reaches point $2; another character when it reaehespoint #3, and a third character when-it reaches point #31. The selector "mechanism" may wired so as to anow'any nlijrnber 'ol charac'ters to be transmittedm sue cession-with'a fixed and predetermined interval ortgimebetween the beginnings or these charac PS. 1

mechanism s,1h weverftne relay D win becom operated -ov r a circmt wnich incl des battery E7, the wfnding of relay D,-.the;arini' s or theseiectbr; its contact i and ground. The relay D will fthen becom locked in its, operatedpos tron, the locking cireuimncmd ng the immature one first frnakerco'ntact of relay 1D, the lower contact of the switch on'ahd 'greunm The switch OF will remain'o rated until the arm Sci the selector mechanism, jreach'eslcohtact #0. The operation or relay D causes the "release magnet RL or the stepping'se1 ct r SL to pe'energ zed and remain energized ohm ,reia Dfis' re eased. The "release magneenn attracts the armature: lever having a "detent which was usedpreviously for holding thelratc'h'et' wheel The attraction or Tever iKL snows the arms to be rerurnea'in a counterclockwise direction to its initial position at contactfi b, "The'circnit for me release magnet RL incl'udes battery E8, the winding of the release mag-mean thearniature and two make contacts of relay D, the lower non or the rela D tothejciicuit is to insure the nigifiatldfi 6! the release magnet RL for a -siifncieht time-to anew the selector arm s to return tons initial 'pesizion' at Contact #0 Thus the release magnet-BL held operated until me arm 5 returns to itsstartlngposltion. The release magnet-'may-also include an upper or non -momma; winding (not shown) {in 'shun t witn mumg 0P or the pur ose orreamin simian-g following the energi'zation ofthe wind= moor.-

It will be observed that the magnet MG of transmitter-distributor ml is operated 'once forfeits operations! reiayo. The 'Steii bY-Stxli selector registers the nrin'iblar'bf obratlbna; or magnet MG by relay C, primar purpose or selector 'SL is to. limit the operations of Il'ih-"gnet Mq-to apredeteimined umber; WithJthe' cnc'uit shown in the drawing the numberof open ations of magnet MG is limited to three, but

byremoving the jumper betweenconta ts #4 and #5 an additional'operation of magnet MG is obtained. By removing additionalrjumpers, the number, of operations of magnet MG may be further increased. -.Furthermore,. if it is not desired to-limit the number of operations of magnet ,MG, all of the jumpers may be omitted or the selector SL may be entirely removed.

It has been observed that by contacting the two swingers at the ,top of switch Z, the transmitter TXD1-is employed for transmittingpulses of current corresponding to teletypewriterchar acters punched in tape 'T over thejlineL. If a different transmitter-distributor such as which may be of a different speedis desired, the switch Z will be operated so as to contact the bottom swingers of the switch. Where the transmitter TXDz is of a different -speed,the pulses of current transmitted over theline -L-will occur at a different ratedetermined; by the speed of the transmitter TXDz, but the spacingbetween the beginnings of each two successive series of pulses will be determined by the time constants of thecircuit ofthis invention which includes the condensers K1 and K2.- In other words, the arrangement of this invention maybe employed to transmit pulses of current corresponding to different characters at any desired speed, yet the spacing between the start of the pulses of the various characters will remain .the same, the

, spacing interval being determined by the timing circuit arrangement .of this inventio In the arrangement shown in Fig. 1 the timing circuit fixes theinterval between the beginnings of transmissionof successive signals or .characters. If it is desired to fix the interval between the completion of the transmission of one signal or character and thebeginningoftransmission of the next succeeding ignal or character, -,the modification shown, in. Fig.' 2 would then be em ployed. In Fig. Z'the lower blade of the offnormal switch OF is connected to ground through a contact W2 which ismechanically, coupled to the contact W1 so that both-contacts W1 and W2 operate simultaneously.

.Thus when the circuit arrangement of Fig. 1- islmodified according to the scheme shown in Fig. 2,'relay C will be released as-soon as contact W1 is opened as heretofore. But relay A will be re-operated only after contact W2 is closed.- Inasmuch as the operation of relay A; determines the beginning of the timing interval, the timing interval will be started after each signal orcharacter is transmitted. V

While it has been shown 7 thatthe teletypewriter transmitters TXDrand TXDz may be used with tape perforated according to a codecorresponding, to teletypewriter characters, it will. be understood that the tape'perforations may correspond to Morse or other codes. Furthermore, it is understood that the transmitter-distributors may be arranged for, the transmission of signals embodied in. or embossed on devices other than perforated tape; this invention may,be used with, transmitters employing code wheels, magnetic tape, photoelectric scanning devices, etc. I

While this invention has been shown anddescribed in certain particular embodiments merely for the purpose of illustration, it will be understood that-the general principles of this invention may be applied-to other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims. J i

Thus the apparatus of Whatisclaimedis:" .fi 1.,The combination of a teletypewriter tape transmitter, stepping mechanism controlling said transmitter so that said transmitter will successively transmit in regular order groups of pulses corresponding to groups of perforations in the tape of said transmitter, each group of perforations corresponding to a different character, and means comprising. an electrical circuit for fixing the interval of time between successive groups of transmitted pulses, said means being independent of the spacing between said groups of; perforations in said tape.

2f. The combination of atape having groups of perforations spaced from each other by fixed distances, each group of pulses corresponding to 'asignal, means including a transmitter and stepping mechanism controlling'said transmitter for successively transmitting said groups of pulses in regular order,.and means-for fixing the interval of time between said groups of pulses, said means comprising an electrical timing circuit.

3. The combination of a teletypewriter tape transmitter, step-by-step apparatus connected to said transmitter to control the operation of said transmitter, means for transmitting groups of pulses of current corresponding to teletypewriter characters to be transmitted by said transmitter, said means including means whereby each group of pulses of current is transmitted in accordance with the progression of said step-by-step apparatus. I

4. The combination of a teletypewriter tape transmitter, means for operating said transmitter step-by-step,- saidv means comprising a step-bystep selector, and a timing circuit connected between said selector and said transmitter for controlling theinterval of time between successive steps of said selector.

5. The combination of a teletypewriter tape transmitter having a perforated tape inserted therein, the perforations of said tape corresponding to teletypewriter signals or characters, stepping mechanism for controlling the operation of said transmitter and an electrical timing circuit for fixing the time interval between the transmissions of said signals or'characters in regular order. Y I 6. The combination of a teletypewriter transmitter having a starting magnet, step-by-step apparatus, means controlled by said step-by-step apparatus for regularly energizing said magnet, and a timing circuit for controlling the interval of time between successive steppings of said stepby-step apparatus. a r

' '7. The combination of a teletypewriter apparatus for transmitting groups of pulses of current controlled by perforations in a tape, means for fixing the interval of time between the beginnings of any two adjacent groups of pulses, said means comprising stepping apparatus and a timing circuit'connected between said stepping apparatus and said teletypewriter apparatus for controlling thetimeinterval between adjacent steps of said stepping apparatus.

8; The combination of means for transmitting signalaan electrical circuit for timing the interval between any two adjacent signals transmitted, and means'for limiting thesignals transmitted to a predetermined number.

9.'In a signaling system, the combination of means for transmitting signals, an electrical circuit for fixing the time interval between adjacent signals transmitted, means for counting the num complete telegraph transmitter for transmitting 1 telegraph signals at predetermined intervals, an electrical timing circuit connected to said transmitter, means including said timing circuit controlling the operation of said transmitter for the transmission of signals at different predetermined intervals, and step-by-step means for operating saidtiming circuit at said latter predetermined intervals.

CHARLES ROBERT WALKER. 

